(1) Field of the Invention
The present invention relates to a carriage lock mechanism of a magnetic recording/reproduction apparatus, especially of a hard disk drive and, more particularly, to a carriage lock mechanism capable of preventing generation of fine dust particles due to friction between the components during a locking operation.
(2) Description of the Prior Art
A typical conventional hard disk apparatus and its carriage lock mechanism will be described below with reference to FIG. 1 and FIGS. 2A, 2B, and 2C.
This conventional apparatus has magnetic disk 11, as shown in FIG. 1. Disk 11 is coupled to and rotated by spindle motor 12.
A carriage mechanism is provided near disk 11. This carriage mechanism includes head arm 13 and head arm supporting block 14, and magnetic head 9 is mounted through suspension 10 to the distal end of arm 13. Head 9 is arranged near the upper surface of disk 11. Arm 13 and block 14 are supported to be rotatable about pivot shaft 15 in a plane parallel to the surface of disk 11.
A voice coil motor is connected to block 14. This voice coil motor consists of coil 16 mounted on block 14 and magnet 17 mounted on a frame. Arm 13 and block 14 are rotated by the voice coil motor, and head 10, mounted on the distal end of arm 13, is moved radially along disk 11 to perform a so-called seek operation. Thus, data is written in or read out from disk 11 by head 9.
This hard disk drive also has a carriage lock mechanism. When disk 11 is not rotated, head 9 is moved to a portion of disk 11 and this portion is not used for data recording. Disk 11 is kept fixed at this position by the above-mentioned carriage lock mechanism. Therefore, even when an external impact acts on the apparatus, damage to head 9 and disk 11 is prevented. The carriage lock mechanism has, as shown in FIGS. 2A, 2B, and 2C, lock member 18 mounted on block 14 and lock pawl 19 engaging with member 18 to perform a locking operation. Pawl 19 is supported by shaft 23, pivoted by a pivoting drive mechanism, and engaged with or disengaged from member 18. The pivoting drive mechanism for pawl 19 consists of spring 22 which biases pawl 19 in an engaging direction, i.e., a direction indicated by arrow 24 in FIG. 2A, and solenoid 21, which pivots pawl 19 in a disengaging direction, i.e., a direction indicated by arrow 26 in FIG. 2B. One end of the plunger inserted in solenoid 21 is connected to pawl 19.
In such a carriage lock mechanism, upon deenergization of solenoid 21, pawl 19 is pivoted in a direction of arrow 24 by a biasing force of spring 22, and hook 25, at the distal end of pawl 19, is engaged with member 18, thereby fixing the above carriage mechanism at a predetermined position, as shown in FIG. 2A. When the hard disk drive is in operation, solenoid 21 is energized, pawl 19 is pivoted in a direction of arrow 26 in FIG. 2B against a biasing force of spring 22, and gap Gl is formed between the distal ends of pawl 19 and member 18, so that block 14 and arm 13 are pivotal. When the hard disk drive is stopped from an operating state, as shown in FIG. 2C solenoid 21 is deenergized, and block 14 and arm 13 are pivoted to predetermined positions by the voice coil motor. In this case, the distal end of pawl 19 abuts against an inclined portion of member 18, and when member 18 is pivoted together with block 14, the distal end of pawl 19 is pushed upward by a height G2 along the inclined portion of member 18 against the biasing force of spring 22. When member 18 is pivoted to a predetermined position, its distal end is engaged with pawl 19.
In such a magnetic recording/reproduction apparatus, especially in a hard disk drive, the magnetic recording density of the magnetic disk is very high, and, upon operation, a magnetic head floats above the magnetic disk. A gap between a surface of the magnetic disk and the magnetic head is very small on the order of, for example, 0.3 to 0.5 .mu.m. For this reason, a head crash occurs in the presence of even extremely small dust particles, destroying the recording data. In order to prevent the operation failure, such a hard disk drive is housed in a clean case having no particles therein.
The above-mentioned carriage mechanism, the carriage lock mechanism, and the like are housed in the case. If a lubricant is applied to movable portions of these mechanisms, particles of the lubricant are formed in the clean case. For this reason, lubricants cannot be used for the mechanisms housed in the case. Thus, when the distal end of pawl 19 abuts against and slides along the inclined portion of member 18, fine dust particles are formed because of direct friction between metals, sometimes resulting in an operation failure of the hard disk drive due to these particles. Especially in this conventional apparatus, when the distal end of pawl 19 is pushed upward along the inclined portion of member 18, an excess load is produced therebetween creating a large amount of particles.
In order to eliminate the above drawbacks, the present invention provides a carriage lock mechanism capable of completely preventing formation of particles during operation.